Fluid pressure device



J. c. COTNER v 2,150,266 FLUID PRESSURE DEVICE Y Filed March 14, 1936 March 14, 1939.*

. INVNTOR. Join C. Cabiate Patented Mar. 14, 1939 PATENr OFFICE 2,150,266 rnnrormssvnn DEVICE John C. Cotner, Iglm'sport, Ind., assigner to I Logansport Mac hine, 11113..,v

Logansport, I nd..

a corporation of Indiana. Applicationmamn 14, 1936, 'serial No. 66,896 y, 'z claim.v (ci. 137-153) Myiinvention relates in general 'to uid pressure devices, and more particularly to fluid depressure of 'the fluid being controlled at a/subm stantially pre-determined value.

Another object of my invention 'is the provisionl of a iiuid pressure device having a major valve for controlling the pressure of the iluid and a 'pilot valveiniluenced by the pressure of the iiuid '15 for controlling' the operation of the major valve.

A still further object of my invention is the provision of a balanced major valve for controlling the pressure of a fluid, together with means for actuating -the movements of the'balanced n major valve by by-passing a portion of the fluid to establish oppositely disposed fluid pressures upon thebalanced major valveand by providing escapement means for the by-pass uid which determines the movements of the balanced major 25 valve.

Another. object of my invention is the provision l of a balanced major valve and a pilot valvefor controlling the balanced condition of the maior valve, together with cushioning means coopera.-

, 3'0 tively associated with the pilotvalve for insuring smooth operation of the pilot valve, as well as for the balanced major valve.

Another object of my invention is the provision of a balanced maior valve and a slide valve as 35 a unit slidable with reference to each other and that .the variations in the uid pressure are reduced -to avery low A 50 Other objects and a fulle'r understanding of my invention maybe had by referring to the following description and claims, taken in con- 'junction with the accompanying' drawinszin which: u `Figure 1 is a cross-sectionalview of a form of my invention and shows the balanced maior valve `and the pilot valve as being constructed in a unit sldably positioned in thelongitudinal centrai cylinder of the b ody of the fluid device and is illustrated as a pressure relief valve; and

Figure 2 is a modified form of the invention shown in Figure 1, in that the valve is illustrated in the form of a poppet valve instead of vavslide valve,

In Figure' 1, I show a cross-sectional view of a l0 Aform of my invention and shows the bmanced major valve and the pilot valve as being constructed in a unit sldably positioned in a longitudinal central cylinder of the body of the fluid device and is illustratedv as a pressure relief valve. l5 This form of my invention comprises generally a bodymember 12, a major slide valve member 16,

a pilot slide valve sleeve 83 surrounding the major-slide valve member-16 and an adjustment screw |04 for varying the'fluid pressure at which 20 the fluid may pass through the fluid device.

The body member 12 has a fluid passage-way 13 and a major longitudinal cylinder 82 extending centrally and vertically of the body member 12.` As illustrated, the pilot slide valvesleeve 83 is provided with two oppositely disposed openings Ill and is reciprocally positioned within the major longitudinal cylinder 82. The major slide valve member 16 is reciprocally mounted in the pilot slide valve sleeve 83. Accordingly when 30 the major slide valve member 16 is raised, uid. is allowed to ow from the inlet iiuid pipe 14, the fluid passage-way 13, through the opening III 'in the wall ofthe pilot slide valvev sleeve 83, from thence it ows into the fluid passage-way -IIU 3s and out through the iiuid pipe 15. 'Ihe major ,sude valve member-.16 is of the' dlfrerenum' type and hasa fluid stepped area' 11 and an oppositely disposed iluid stepped area 18. Therefore, the pressure of the fluid tending to'raise the major 40 slide valve member 16 is 'the differential action of the iiuid pressure acting upon the uid stepped area 11 minus ,the fluid pressure acting upon the iiuid stepped area 18. The lower end of the major slide valve member 16 is provided with a vpiston portion and isreciprocally mounted with- -in the longitudinal opening 30 Yprovided in the .lower end Vof the body member 12. Below the lowermost endof the major slide 'valve member' l 16, there i"s"'a fluid cavity 89, which is enclosed 5o by means of a threaded plug 8|.'

The uppermost part bf the maior slide vvalve member 16 is in the form of ,a piston and is 1 'e' ciprocally mounted within the pilot slide valve sleeve 83.. i

In order to form a piston chamber 93 above after iiowing through the grooves ||4 ffows out the major slide valve member 1,6, I utilize a body cylinder cap 92 which has Ya lowermost portion extending snugly, but freely, into the uppermost vinner end of the pilot slide valve sleeve 83. 'I'he body cylinder cap 92 is provided with an out- Lwardly extending flange 94 'and is connected to an internal shoulder 91 of the body member 12 by means of the cap screws 95. A piston spring 88 is interposed between a piston recess 90 and the lowermost end of the body cylinder cap 92. This spring 88 in the absence of the uid pressure tends to bias-the major slide valve member 16 in its closed position.Y Extending through the openings |00 in the body member cylinder cap 92 is a slidable plunger assembly 99 having plungers which engage a ange 84 provided in the top of the pilot slide valve sleeve 83, The slide plunger assembly 99 is controlled by the adjustment screw |04'through means of an ad-v der cap 92, the slidable plunger assemblyf99, and' the adiustment spring. |0| are assembled in the uppermost part of the body member 12 which constitutes a hollow portion having a containing wall |06. VThe upper end of the containing wall |06 is enclosed by means of` a body cap' |05 by means of the cap screws |01. In order to make a good uid tight assembly, there is positioned a gasket |09 beneath, the body cap |05. The adjustment screw |04 is threadably engaged to a centrally positioned threaded opening in the body cap |05 and is arranged to vary the tension o! the adjusting spring |0| to control the operation'of the pilot slide valve sleeve 83. In order to bias the pilot slide valve sleeve 83 upwardly against the lower end of the plungers of the slidable plungerassembly 99, I position a spring 85 -between the outwardly extending flange v84 of the pilot" slide valve sleeve 83 and a stepped shoulder 86 in the body member 12.

'I'he uid in the fluid passage-way 13 is allowed to ilo' through a. restricted by-pass ||2 that interconnects the stepped shoulder 11 with the top surface of the major slide valve member 16. In order to vary the resistance to the ow -of the uid through the restricted by-pass ||2,

I utilize' a replaceable orifice ||3 threadably engaged in the upper .portion of the major slide valve member 16. the ilow of the iiuid through the restricted by. pass ||2 may be selected by means of choosing the proper size of replaceable orice ||3 to accommodate any particular design of a fluid device embodying the features of my invention. The by-pass fluid entrapped in the piston chamber 93 is allowed to escape tov the iiuid passageway- ||0 and out through the exit pipe 15 when the pilot slide valve sleeve 83 is raised, This escapement is effected by allowing the fluid to ow through oppositely disposed fluid openings |4 into the grooves ||1 'provided in the externalwall of the pilot slide valve sleeve 83. As illus-v trated, the upper end of the grooves I|1 is tapered"soas to provide a gradual opening as Therefore, the resistance to into the iluid passage-way ||0, through a duct ||5. Also the fluid which may leak' past theI lowermost end of the major slide valve member 16 into the fluid cavity 89 is allowed to escape to the fluid passage-way ||0 by means of the fluid duct H6.

As illustrated, the piston area 19 on top of the major slide valve member 16 is greater than the diiierential area of the stepped area 11 minus the` stepped area 18 which means that under conditions of equal uid pressures upon these areas,

the piston is hydrostatically urged downwardly.

In explaining the operation of my device, let it be assumed thatl the pressure of the uid is below the pre-determined setting as determined by the adjustment screw |04. Under this condition, the uid .in the iiuid passage-way 13 ows through the restricted by-pass ||2 and the restricted orifice 3 into the piston chamber 93. After the piston chamber 93 is full, the pressure of the by-pass fluid in the piston chamber 93 is the same as the pressure in the fluid passageway 13. Therefore, the hydrostatic force of the iluid in piston chamber 93, acting upon the upper end 19 of the balanced major slide valve member 16, is greater than the differential hydrostatic force of the vfluid in the passage-way 13, acting upon the stepped shoulder 11. and 18.- This means that the major slide valve member 16 under this conditionV is hydrostatically forced downwardly in its closed position and prevents the uid' within the uid passage 13- from escap- I ing. Also under this assumed condition, the pilot slide valve sleeve 83 is urged downwardly in its closed position by reason of the fact that the tension of the spring pressure |0| is greater than the hydrostatic pressure of the uid acting upon the lower peripheral edge 81 oi the pilot slide valve sleeve 83. Accordingly the by-passed uid entrapped in the piston chamber 93 cannot escape. y

Now let it be assumed that the pressure of the uid being controlled exceeds a pre-determined value as set by the adjustment screw |04. Under this condition, the hydrostatic force of the fluid acting upon the lower peripheral edge 81 of the pilot slide valve 83 is greater than the opposing downward force of the adjusting spring |0|. As a result, the pilot slide valve sleeve 83 is urged upwardly and the longitudinal grooves ||1 in terconnect the piston chamber 93 to the exit fluid passage ||0 through the fluid duct ||5. This means that under the opened condition of the pilot slide valve sleeve 83, the iuid entrapped in the piston chamber 93 flows through the openings ||4 in the wall of the pilot slide valve sleeve 83, the grooves ||1, the uid duct ||5, the exit fluid passage-way ||0 and out into the exit pipe 15. Just as soon as the by-passed iluid en-y trapped in the piston chamber is allowed to escape, the pressure of the entrapped iluid is materially reduced to the point that the value of the hydrostatic force of the iluid tending to raise the major slide valve member 16 acting differentially against the stepped shoulders 11 and 18, is greater than the hydrostatic force acting downwardly against the top piston area 19. of the major slide valve member 16.*;This hydrostatically forces the major slide valve member 16 upwardly and allows the fluid in the fluid passage-way 13 to flow through the openings in,

the wall of the pilot slide valve sleeve 83 and into the exit uid passage-way ||0, where the the pilot slide valve sleeve is raised. The uidb uid escapes through the exit pipe 15. It is, I

noted that Lthe resistance oii'ered to the ilow. of the iluid through the restricted by-pass I|2 and the restricted oriilce II'3 is greater than the resistance oilered to the flow of the iluid through the fluid duct which connects the piston chamber 83 in communication with the' exitv fluid chamber IIO. As a result, the uid in the piston chamber 93 is allowed to escape when the pilot slide valve sleeve 83 is opened, at a faster ratel than that which the iluid can ilowinto the piston chamber 93 through the restricted by-pass II2 and the restricted -orifice II3.

To give gradual and smooth operation, Vthe upper end of the fluid grooves II1 of the pilot slid. valve sleeve 83 isgradually tapered. This means 'that in the early stages of the opening of the pilot slide valve, the .escapement oi the uid from the piston chamber 93 is gradual. Consequentlv, the upper movement of the major slide valve member 13 is likewise. gradual, which in 'turn, provides a gradual escapement of the iluidl from the passage-way 13 into the .exit passageway I I0. 'The gradual escapement of the fluid from the fiid passage-way 13 into the exit passage-way I8 reduces the pressure oi' the iluid4 in the passage-way 13 and causesthe pilot slide valve sleeve 84 to be again closed, whereupon the major slide valve member 19 moves downwardly v Atiorzo! the pilot slide valve 83.l

and 'closes the uid openings III in the wall of the pilot slide valve sleeve 83. The cycle of raising and lowering the major slide valve member 18 is gradually repeating. itself and in .actual operation, the major valve member 18 is balanced and assumes a position corresponding to the posiis noted that in the'. operation of my device that the major slide valve member 18 does not vention from that shown in Figure 1 in'that the grooves |'|1, and thence out v|22 into the exit pipe |28.

' openuntil after the pilot slidev valve sleeve 83 is raised sufdciently and connects the piston chamber 93 vwith the exit uid passage-way H0. BY reason of -thisvconditiom the variations in the iiuid pressure are reduced to a very small As illustrated, the flange 34 on the upper end of the pilot slide valve sleeve 83 is provided with an opening |24 and the outward ange 94 on the body cylinder cap 92 is likewise provided with an opening |23. This means that whatever fluid lescapes between the clearance of the outward flange 34 of the pilot slide valve sleeve 83 and through the clearance around the plungers of the slidable plunger assembly 99 may drain to the exit valve passage-way I I8.

In this embodiment of my invention, the spring 85 constitutes a cushioning device to give a smooth operation to the .pilot slide valve sleeve' 83.

In Figure 2, I show a modified form of the indiilerential .major slidevalve member 18 is reiiow from the iluid passage-way 13 past the major .poppet valve ||9 and out through the exit pipe |28. 'I'he threaded opening in which the -exit y pipe 15 screws in Figure 1 is plugged with a threaded'plug I2I. In this modied form of my invention, the uuid in the piston chamber 93 is allowed to escape through the openings |l4 in the wall of the pilot slide valve sleeve83, the through a uid duct 'i The operation oi the device shown in Figure 2 is substantially thesame as that' described with reference to that shown in Figure 1. That is to say, .the fluid is allowed to ow when it attains a pre-determined pressure as determined'by the .aisoce l l setting of the adjustment screw |84v and pre-l vented trom flowing when the pressure fallsI below the setting ofthe said pre-determined value.

Although I have described my invention 'with a certain degree of particularity, it is understood that the present disclosure has been made onlyv by way oiQexample and that numerous changesV in the details of construction -and the combina-v tion and arrangement oi parts may be resorted -to without departing from the spirit and the p bination, a body member, a major .valve having a movable member slidably mounted in the body member, said movable valve member having two i oppositely disposed iiuidf po'rtions for hydrostatically actuating the movablevalve member, said` oppositely disposed fluid portions being in communication with each other through a restricted,

by-pass, and a pilot valve sleeve slidably mounted around the movable valve member for controlling the pressure oi the uid acting against one oi?l said oppositely disposediluid portions to govern the operation oi the said movable valve member, said Vpilot valve sleeve being controlled in response to the pressure of the fluid on the entrance side oi' the major valve. y

2. VA iluid pressure device comprising, in combination, a body member, a major valvehaving av movable member 'slidably mounted in thevbody l member, said movable valve member having two oppositely disposed fluid portions i'or-hydrostai'iv .cally actuating the movable valvemember. said \rppositely disposed fluid portions being in communication with each other through a restricted b y-pass. a pilot valve sleeve .slidably mounted around the movable valve member for controlling the pressure of the fluid acting against one of said oppositely disposed fluid' portions to governthe operation oi the said movable valve member, said pilot valve being controlledin response to the pressure of the fluid on the entrance side of the major valve, and adjusting means for varying the operation of the pilot valve.

3. A fluid pressure device comprising, in'combination, a body member, a major valve having a movable memberA slidably mounted in the body member, said movable valve member having .two oppositely disposed uid .portions for hydrostatically yactuating the movable valve member, said oppositely disposed iluid portions being in communication witheach other through a restricted bypass, a pilot valve sleeve slidably mounted around the movable valve member for controlling the pressure of the iluid acting against one of said oppositely disposed iluid portions to govern the operation oi the said movable valvefmember. said pilot valve being controlled" in response .to the pressure oi' the fluid on the entrance side-of the major valve, and cushioning means for insuring a' smooth operation oi the pilot valve.. 4. A uid pressure device comprising. in com bination, a body member, a major valve-having a movable member slidably mounted' in the body member, said movable valve member having two oppositely disposed iluid portions iorhydrostatically actuatingthe movable-valve. member, said Y oppositely disposed iluid portions being in communication with each other through a restricted by-pas's, a pilot valvesleeve slidably mounted around the frnovable valve member for controlling the pressure ofthe fluid acting' against one of said' oppositely disposed iluld portions to govern the pilot valve being controlled in response tothe pressure of the iluid on the entrance side of the major valve, adjusting means for varying the through a restricted by-pass, .and a pilot valve slidably mounted against the major valve member for controlling the iiuid pressure in onel of -the opposing uid chambers to govern the reciprocable movements of the major valve member, the movements of the said pilot valve being controlled in response to the fluid pressure in the other iluid chamber,v adjustable means for varying the operation of the pilot valve, and-cushioning means for insuring a smooth operation of the pilot valve.-

6. A iluid device comprising, in combination, a body member', a major valve member slidably mounted Ain the body member, said body'm'ember having two opposing uid chambers between which the major valve member may Vreciprocate operation oi' the said movable valve member, said incident to changeable num pressures-in the opposing uid chambers, said opposlng'iluid chambers being always in communication with each other through a by-pass, and a pilot valve slidably mounted against the major valve member for controlling the uid .pressure in one of the opposig uid chambers to govern the reciprocable movements of the major valve member, the movements of the said pilot valvebeing controlled in response to the fluid pressure in the other :duid chamber.

'7. A iiuid device comprising, in combination, a body member, a major valve member slidably mounted in the body member, said bodyV member having two opposing Yiiuid chambers between which the major valve member mayreciprocate incident to changeable iiuid pressures in the Y opposing fluid chambers, saidv opposing fluid chambers being always in communicationvwith each other through a by-pass. a pilot valve slid-l ably mounted against 4the major valve member for l controlling the iiuid pressure in one of the opposing fluid chambers to govern the reciprocable movements of the major valve memb, the movements of the said pilot 'valve being'controlled in response to theiluid pressure in`the other fluid chamber, and adjustable means for varying the operation oi the pilot valve. Y'

JOHN C. COTNER. 

